The Atlantic | Oceans in Disney's Moana

Posted
June 01, 2017

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The Algorithms behind Moana's Gorgeously Animated Ocean

In the early days, when motion pictures were still new, filming the ocean was a radical idea.

A surface-level shot of the waves was certainly feasible, but capturing footage of swaying undersea fauna, swimming fish, and marbled sunlight dancing on the seafloor? The consensus was: It couldn’t be done.

In fact, it could be. A century ago, the brothers John Ernest and George Williamson, the sons of a sea captain and inventor, would prove it. To do so, the Williamsons turned to a piece of technology their father had designed for divers in undersea repair and salvage jobs. The device was a series of flexible concentric tubes, “interlocking iron rings that stretched like an accordion,” as the Library of Congress puts it, made to suspend from a specially outfitted ship so that a diver could descend into a watertight chamber below. At one end of the tube was the boat on the surface of the water; at the other, the submersible room....

Splash is a “fluid solver” that plugs into Houdini, third-party 3-D animation software. To use the solver, effects specialists would define the area they wanted to simulate—say, a section of water around an animated boat—then use a setting to determine what the ocean condition should be like to begin with.